I got it from
Waytek. Here is their
catalog.
The only thing about these guys is that they are a distributor, so they sell most things in bulk. But the cool part is, it's so cheap it didn't even matter for me. I was able to just buy one relay/fuse block, but I had to buy like 50 terminals and seals of each size. So I've just got extra terminals and seals laying around.
Really a pretty cool source for wiring parts. Especially if you want to do weather pack connectors.
The "junction" block I spoke of earlier is actually very similar to what is on the passenger side of our trucks, I just added another from a Corvette on the driver's side near the location of the original "3-way" junction. Got mine used off ebay for like $3, you can get new ones for $20 or so I think.